From the back of the book:
"Character concepts are not simply about adding to a character's abilities. In many respects they are the character; or at least the germ of that character. Even the Man With No Name, a mysterious drifter who saves whole towns from evil, has a nugget of character that statistics and skills cannot quite capture. He is not just another renegade who can fight - as soon as he walks into play, everyone knows he has a unique, if shrouded, background. This is the core of character concepts, the reason for their success, for they are the starting point of an adventure. Even before the characters meet, each can have a core vision and attitude from the very beginning of play. Character concepts are about roleplaying - the only reason for the benefits and penalties given in every case k to properly flesh out how these particular individuals would be slightly - or substantially - different from others of their kin."